Answer is: <span>the mass of the excess reactant (ethane) leftover is 90.135 grams.
</span>Chemical reaction: 2C₂H₆(g) + 7O₂(g) → 4CO₂(g) + 6H₂O<span>(g).
m(</span>C₂H₆) = 152 g.
n(C₂H₆) = m(C₂H₆) ÷ M(C₂H₆).
n(C₂H₆) = 152 g ÷ 30 g/mol.
n(C₂H₆) = 5.067 mol.
m(O₂) = 231 g.
n(O₂) = 231 g ÷ 32 g/mol.
n(O₂) = 7.218 mol; limiting reactant.
From chemical reaction: n(O₂) : n(C₂H₆) = 7 : 2.
n(C₂H₆) = 2 · 7.218 mol ÷ 7.
n(C₂H₆) = 2.0625mol.
Δn(C₂H₆) = 5.067 mol - 2.0625 mol.
Δn(C₂H₆) = 3.0045 mol.
Δm(C₂H₆) = 3.0045 mol · 30 g/mol = 90.135 g.
The cornea is the outer clear, round structure that covers the Iris and the pupil. The Iris is the colored part of the eye.
Answer:
T = 377.2 K, Less than
Explanation:
The thermodynamic quantity used in predicting whether a reaction is spontaneous or not is the gibbs free energy.
It's relationship with ΔH⁰ and ΔS⁰ is given as;
ΔG° = ΔH° - TΔS°
Basically, a negative value of ΔG° means the reaction is spontaeneous.
To obtain the calculated vale of T,
ΔS° = ΔH°/T
T = ΔH° / ΔS°
T = 377.2 K
Let's calculate the value of ΔG° at that temperature.
ΔG° = ΔH° - TΔS°
ΔG° = − 46700 - 377.2(− 123.8)
ΔG° = 0 (approximately, values are due to the rounding off)
At ΔG° = 0 the reaction is at equilibrium.
To find if the reaction is spontaneous at lower or hugher temperature than the calculated temperature, we would be substituting the value of T with a smaller (random) value and also a larger (random) value.
Larger T (390K)
ΔG° = ΔH° - TΔS°
ΔG° = − 46700 - 390(− 123.8)
ΔG° = - 46700 + 48,282
ΔG° = 1582 J/mol
Smaller T (350K)
ΔG° = ΔH° - TΔS°
ΔG° = − 46700 - 350(− 123.8)
ΔG° = - 46700 + 43330
ΔG° = -3370J/mol
This means the temperature would be lesser than the calculated value for it to be spontaneus.
Answer: There are 
molecules present in 7.62 L of 
at 
and 722 torr.
Explanation:
Given : Volume = 7.62 L
Temperature = 
Pressure = 722 torr
1 torr = 0.00131579
Converting torr into atm as follows.
Therefore, using the ideal gas equation the number of moles are calculated as follows.
PV = nRT
where,
P = pressure
V = volume
n = number of moles
R = gas constant = 0.0821 L atm/mol K
T = temperature
Substitute the values into above formula as follows.
According to the mole concept, 1 mole of every substance contains 
atoms. Hence, number of atoms or molecules present in 0.244 mol are calculated as follows.
Thus, we can conclude that there are molecules present in 7.62 L of at and 722 torr.
Answer:
D. The higher energy chair conformation contains two axial methyl groups.
Explanation:
The diaxial trans-1,4-dimethylcyclohexane has the highest energy (the least stable) and the diequatorial chair conformation has the lowest energy (the most stable).
The diaxial conformation has a higher energy due to the interaction between the methyl groups.
